Bag with crimped portion to retain slider

ABSTRACT

A reclosable plastic bag ( 10 ) having two panels ( 15 ) of plastics sheet or film joined to, or integral with, each other, or a combination of both, to define a bag with an opening ( 13 ), with separable fastening means ( 14 ) of one or more interengagable elongate fib/groove configurations ( 14   a,    14   b ) are provided to close the opening ( 13 ). A slider ( 100 ) is positioned in straddling relationship to the fastening means, and includes a support member ( 111 ) over-lying the opening to the bag and straddling the fastening means, and also carrying a separating finger ( 112 ) to engage with and separate the fastening means when the slider is moved to a first end of the fastening means in a bag opened condition, and a pair of legs ( 113 ) extending from said support member to force the fastening means into interengaging relationship when the slider is moved to a second end of said fastening means in a bag closed condition. Flanges ( 119 ) on the legs extend beneath the fastening means to retain the slider on the bag. The edges ( 19 ) of the panels of the bag adjacent the second end of the fastening means are bonded together with a portion thereof between the bonding and said fastening means being crimped to define a torturous path ( 20   a ) between the panels into which path the separating finger ( 112 ) the slider is received to be gripped by the portions of the panels on either side of the torturous path to thereby retain the slider in the bag closed condition.

TECHNICAL FIELD

This invention relates to improvements in reclosable plastic bags andslider assemblies, that is, plastic bags which can be repeatedly openedand closed to receive and retrieve contents, and sometimes known as“zipper bags”, whilst a plastic slider is used for opening and closingsuch reclosable plastic bags. Such bags are formed from a pair offlexible plastic sheets or panels having top edges with separablefastening means extending along the lengths of the top edges andtherefore at the opening of the bag with the slider straddling theseparable fastening means.

BACKGROUND ART

Such bags conventionally are of rectangular configuration formed from anelongate plastic sheet or film folded upon itself to form two panels andsealed together along their opposite side edges with an opening definedby the free edges of the panels. The opening is adapted to be repeatedlyopened and closed by fastening means formed from a rib extending acrossone of the panels below the opening of the bag and interengaging in agroove formed between, and therefore defined by, two ribs extendingacross the other panel and also below the opening of the bag. Twoparallel extending ribs on either sides of the rib which engages withinthe groove serve to capture the ribs within the defined groove.

The ribs and grooves are shaped and dimensioned so that the rib fitstightly within its associated groove and the ribs defining theassociated groove deform to allow the rib to enter and to be capturedwithin its associated groove.

The sliders conventionally have a separator finger carried by acomplimentary structure which has a transverse finger support memberfrom which legs depend and with lower inwardly directed flanges whichengage beneath the separable fastener means to hold the slider on thebag and around the fastener. The finger serves to separate the fasteneras the slider is moved in one direction along the separable fastenermeans, whilst the legs of the slider press the rib and groove of thefastener means together to close the fastener when the slider is movedin the opposite direction.

However, such bag/slider assemblies are subject to difficulties withholding the slider in position when moved to its bag closed position,and it is an object of the present invention to minimise, if noteliminate, this difficulty.

DISCLOSURE OF THE INVENTION

In accordance with the present invention there is envisaged a reclosableplastic bag having at least two panels of plastics sheet or film joinedto, or integral with, each other, or a combination of both, to define abag with an opening, separable fastening means of one or moreinterengagable elongate rib/groove configurations to close said opening,a slider positioned in straddling relationship to said fastening means,said slider including a support member overlying the opening to the bagand straddling said fastening means, and also carrying a separatingfinger to engage with and separate said fastening means when said slideris moved to a first end of said fastening means in a bag openedcondition, and a pair or legs extending from said support member toforce said fastening means into interengaging relationship when the saidslider is moved to a second end of said fastening means in a bag closedcondition, means on said legs and extending beneath said fastening meansto retain said slider on said bag, and wherein the edges of said panelsof said bag adjacent said second end of fastening means are bondedtogether with a portion thereof between said bonding and said fasteningmeans being crimped to define a torturous path between said panels intowhich path part of the slider is received to be gripped by the portionsof said panels on either side of said torturous path to thereby retainsaid slider in the bag closed condition.

Preferably at least one elongate strengthening rib is provided adjacent,and parallel, to said fastening means and on one or each of the panelsof the bag inwardly from said fastening means.

Preferably the, or each, elongate strengthening rib cooperates with saidslider retaining means extending beneath said fastening means to alignthe slider with said fastening means.

Preferably the, or each, said elongate strengthening rib and said sliderretaining means are configured to produce an audible sound and/ortactile feel as said slider is moved along said bag opening.

Preferably the part of said slider which is received within thetorturous path is said separating finger.

BRIEF DESCRIPTION OF THE DRAWINGS

One preferred embodiment of the invention will now be described withreference to the accompanying drawings, in which;

FIG. 1 is a perspective view of the slider/bag assembly in the bagclosed condition,

FIG. 2 is a perspective view of the slider/bag assembly in the bagopened condition,

FIG. 3 is a perspective view of the slider/bag assembly during theprocess of moving to or from the bag closed condition,

FIG. 4 is a side view of the slider/bag assembly of FIGS. 1 to 3,

FIG. 5 is a transverse cross-sectional view of the assembly of FIG. 4,and

FIG. 6 is a view from beneath of the assembly of FIGS. 4 and 5.

BEST MODE FOR CARRYING OUT THE INVENTION

In this preferred embodiment, the reclosable plastic bag after assembly,is generally indicated as 10. The plastic bag is formed from an extrudedtube of plastic sheet or film which when flattened produces a fold line11 which will define the bottom of the bag, and which therefore producesa pair of panels 15 which are thereafter sealed along their oppositeside edges 12 to provide a plastic bag having an opening 13 at the topof the bag when the other side of the tube is slit. The opening 13 isadapted to be repeatedly opened and closed by an extruded fasteningmeans 14, and consisting of a rib 14 a extending across the width of onepanel at the opening of the bag and below the opening of the bag, andalso engaging and captured within a groove 14 b defined by a pair ofribs 14 c extending across the width of the other panel of the bag atits opening. A pair of ribs on either side of the rib 14 a, whichengages within the groove 14 b, serves to also capture the ribs 14 cwhich define the grooves.

A plurality, in this preferred embodiment two, parallel strengtheningribs 18 are also extruded beneath the fastening means 14, to in effectbear some of the forces applied to the fastening 14 and thus minimisethe possibility of splitting or breaking of the bag inwardly of thefastening means, whilst at the same time strengthening the panels of thebag adjacent the fastening means to provide additional rigidity toassist in aligning the interengaging rib/groove configuration whenclosing the bag.

The fastening means 14, and the strengthening ribs 18, are all extrudedwhen the tube from which the bag will be formed is extruded and beforethe tube is slit.

The strengthening ribs 18 may be formed by altering the profile of theextrusion die, or by injecting plastics material directly onto thesurface of the tube as it is being extruded, or by a forming processthrough a grooved die head also when the tube for the bag is beingextruded. A more manufacturing and material costly laminating processcould also be used if necessary. In the case of laminated profiles,multi-layers could be laminated which makes the bag more suitable forfreezer and cold storage applications.

Both ends of the upper edges of the panels are bonded together at 19such as by heat and pressure welding, whilst in accordance with theinvention a portion 20 of the upper edge of the panels between thebonded portion 19 at the bag closed end of the fastening means, and theadjacent end of the fastening means, is configured by crimping to definea torturous path 20 a between the edges of the panels over the length ofthe portion 20 and adapted to receive and retain the separating finger112 of the slider 100 (to be later described) in the bag closedcondition. The portion 20 and the adjacent bonded portion 19 also serveto prevent the slider moving off the end of the opening of the bagwithout the need for raised end portions or cut-outs that have had to beused with some known assemblies.

The slider of this preferred embodiment is moulded as a one pieceplastic component. Alternatively the slider could be made from aplurality of separate parts which are clipped together.

The slider, generally indicated as 100, of this preferred embodiment ofthe invention includes a support member 111 to the underside of which ismoulded the separating finger 112, and may be of any number of types ofconfigurations, and which would normally be moulded with the remainderof the slider. The support member on opposite side edges thereof hasdepending legs or panels 113 extending along the opposite longitudinalsides respectively. A multiplicity of ribs (not shown) may be formed onthe outsides of the panels 13 to assist in finger gripping duringmovement of the slider during opening and closing the fastener means ofthe plastic bag.

An end stop 121 formed on the support member 111 engages the bonded end19 at the bag open position of the slider to prevent the slider frommoving off that end of the bag opening, once again without the need forraised end portions or cut-outs that have had to be used with some knownassemblies. The lower ends of the panels towards one end thereof carryflanges 119 which engage beneath ledges 120 formed beneath the fasteningmeans 14 of the plastic bag, whilst the cooperation of flanges 119 ofthe slider with the strengthening ribs 18 of the bag serves to align theslider with the fastening means.

In addition the, or each, strengthening rib 18 and the flanges 119 maybe configured, such as by spaced apart ribs along one interengaging withspaced apart grooves on the other, and such that when the flanges 119are moved relative to the strengthening ribs 18 an audible sound and/ortactile feel is produced as the slider is moved along the bag opening.

1. A reclosable plastic bag having at least two panels of plastics sheetor film joined to, or integral with, each other, or a combination ofboth, to define a bag with an opening, separable fastening means of oneor more interengagable elongate rib/groove configurations to close saidopening, a slider positioned in straddling relationship to saidfastening means, said slider including a support member overlying theopening to the bag and straddling said fastening means, and alsocarrying a separating finger to engage with and separate said fasteningmeans when said slider is moved to a first end of said fastening meansin a bag opened condition, and a pair or legs extending from saidsupport member to force said fastening means into interengagingrelationship when the said slider is moved to a second end of saidfastening means in a bag closed condition, means on said legs andextending beneath said fastening means to retain said slider on saidbag, and wherein edges of said panels of said bag adjacent said secondend of fastening means are bonded together with a portion thereofbetween said bonding and said fastening means being crimped to define atorturous path defined by transversely directed projections between saidpanels into which path part of the slider is received to be gripped bysaid projections of said panels on either side of said torturous path tothereby retain said slider in the bag closed condition.
 2. A reclosableplastic bag as claimed in claim 1, wherein at least one elongatestrengthening rib is provided adjacent, and parallel, to said fasteningmeans and on one or each of the panels of the bag inwardly from saidfastening means.
 3. A reclosable plastic bag as claimed in claim 2,wherein the, or each, elongate strengthening rib cooperates with saidslider retaining means extending beneath said fastening means to alignthe slider with said fastening means.
 4. A reclosable plastic bag asclaimed in claim 1, wherein the, or each, said elongate strengtheningrib and said slider retaining means are configured to produce an audiblesound and/or tactile feel as said slider is moved along said bagopening.
 5. A reclosable plastic bag as claimed in claim 1, wherein thepart of said slider which is received within the torturous path is saidseparating finger.
 6. (canceled)